Steering control device

Abstract

A steering control device controls a steering system including a reaction force motor that gives a steering reaction force to a steering shaft and a turning motor that turns a turning wheel in a state where dynamic power transmission from the steering shaft is blocked. The steering control device includes a processor that executes a reaction force setting process and a reaction force giving process. In the reaction force setting process, the processor sets the steering reaction force using a predetermined-component reflecting process. In the reaction force giving process, the processor operates the reaction force motor such that the reaction force motor gives the steering reaction force set by the reaction force setting process.

What is claimed is: 
     
         1 . A steering control device configured to control a steering system including a reaction force motor and a turning motor, the reaction force motor giving a steering reaction force to a steering shaft, the turning motor turning a turning wheel in a state where dynamic power transmission from the steering shaft is blocked, the steering control device comprising a processor configured to execute a reaction force setting process, a reaction force giving process, and an interlocking process, wherein:
 in the reaction force setting process, the processor sets the steering reaction force using a predetermined-component reflecting process;   in the reaction force giving process, the processor operates the reaction force motor such that the reaction force motor gives the steering reaction force set by the reaction force setting process;   in the predetermined-component reflecting process, the processor reflects, in the steering reaction force, a predetermined component of a frequency signal that is given to the turning wheel;   in the interlocking process, the processor alters one of a first pair of variables consisting of a reflection specifying variable and a variable that determines a change in the steering reaction force with respect to an operation of the steering shaft, depending on another of the first pair; and   the reflection specifying variable specifies a way to extract the predetermined component.   
     
     
         2 . The steering control device according to  claim 1 , wherein:
 the processor is configured to execute a shaft force gradient calculating process;   in the shaft force gradient calculating process, the processor calculates a shaft force gradient;   the shaft force gradient is a rate of a change in a force against a rotation of the steering shaft with respect to a change in a rotation angle of the steering shaft; and   in the interlocking process, the processor further alters one of a second pair of variables consisting of the reflection specifying variable and the shaft force gradient, depending on another of the second pair.   
     
     
         3 . The steering control device according to  claim 2 , wherein:
 the reaction force setting process includes an assist amount setting process and a shaft force setting process;   in the shaft force setting process, the processor sets a shaft force against a rotation operation of the steering shaft by a driver;   in the assist amount setting process, the processor sets an assist amount by which the driver is assisted to rotate the steering shaft; and   the steering reaction force is determined depending on a value resulting from subtracting the assist amount from the shaft force.   
     
     
         4 . The steering control device according to  claim 3 , wherein in the shaft force gradient calculating process, the processor calculates a change amount of the shaft force set by the shaft force setting process with respect to the change in the rotation angle of the steering shaft. 
     
     
         5 . The steering control device according to  claim 2 , wherein in the interlocking process, the processor alters the reflection specifying variable, using the shaft force gradient as an input. 
     
     
         6 . The steering control device according to  claim 3 , wherein:
 the predetermined-component reflecting process includes a predetermined-component extracting process and an extraction altering process;   in the predetermined-component extracting process, the processor extracts the predetermined component depending on the reflection specifying variable;   in the extraction altering process, the processor alters the reflection specifying variable;   in the shaft force setting process, the processor sets the shaft force depending on a shaft force specifying variable that specifies a relation of the shaft force with respect to the change in the rotation angle of the steering shaft; and   in the interlocking process, the processor alters the shaft force specifying variable, using the reflection specifying variable as an input.   
     
     
         7 . The steering control device according to  claim 1 , wherein:
 the reaction force setting process includes a basic assist amount setting process and a shaft force setting process:   in the shaft force setting process, the processor sets a shaft force against a rotation operation of the steering shaft by a driver;   in the basic assist amount setting process, the processor sets a basic assist amount by which the driver is assisted to rotate the steering shaft, using a steering torque as an input;   the steering reaction force is determined depending on a value resulting from subtracting the basic assist amount from the shaft force;   in the interlocking process, the processor further alters one of a second pair of variables consisting of the reflection specifying variable and an assist gradient, depending on another of the second pair; and   the assist gradient is a rate of a change amount of the basic assist amount with respect to a change amount of the steering torque.   
     
     
         8 . The steering control device according to  claim 7 , wherein in the interlocking process, the processor alters the reflection specifying variable, using the assist gradient as an input. 
     
     
         9 . The steering control device according to  claim 7 , wherein:
 the predetermined-component reflecting process includes a predetermined-component extracting process and an extraction altering process;   in the predetermined-component extracting process, the processor extracts the predetermined component depending on the reflection specifying variable;   in the extraction altering process, the processor alters the reflection specifying variable; and   in the interlocking process, the processor alters the assist gradient, using the reflection specifying variable as an input.